Remember when we first discovered what kind of man Walter White really was? It came in the final moments of season four. I won't divulge spoilers, but the episode sets the pace for Walt's rapid ascension as a drug kingpin and his tailspin as a human being in the current season.

Right after Walt's smug assertion, "I won," the opening notes of Danger Mouse's "Black" creep in. The song blends the haunting vocals and strings emblematic of a James Bond theme with some California guitar. But the real message is in the lyrics.

Until you travel to that place you can't come back
Where the last pain is gone and all that's left is black
...
Bright nights cease coming to me, and
Some day they'll punish my deeds, and they'll find all the crimes
...
Fooled them, hoping to seem
Like the sweat of evil,
But the product of greed, and
It's not a mask, so be honest with me
They can't afford to ignore that I'm a disease
Practical, since we had to be, and
When they were old they came back to me
And they tried, oh they tried

The dark foreboding of Norah Jones' voice underscores what the viewer has been trying to ignore all season: Walt is no longer the good guy.